week 4 Flashcards
volume of distribution
(L) is the apparent volume that a drug distributes into, based on dose amount and serum concentration.
clearance
(L/h) is the volume of blood cleared of drug per unit time. The main routes are renal excretion and hepatic metabolism.
elimination rate constant. give equation
(1/h) is the rate of decline of concentration.
k(/h) = Cl (L/h) / V (L)
elimination half-life. give equation,
(h) is the time for concentration to fall to half
T1/2(h) = -Ln (0.5) / k
how many half-lives is steady state
5
aminoglycoside antibiotic examples
gentamycin, amikacin, tobramycin
estimating dose equation
Dose(mg) amount = target Cmax (mg/L) x V(L)
aminoglycosides are highly __, water-soluble compounds therefore have a __ oral bioavailability and are administered IV.
polar
low
glycopeptide antibiotics examples
vancomyin and teicoplanin
vancomycin active against gram positive or negative infections?
positive
gentamycin used in gram negative or gram-positive infections?
negative
what is vancomycin infusion reaction and what is it caused by?
It is caused by a histamine release following degranulation of mast cells and basophils. An erythematous rash spreads across face, neck and upper torso with burning and severe pruitus. Patient may become hypotensive, dizzy agitated and experience headache, chills, fever, paraesthesia, chest pain, dyspnoea
what rate is vancomycin administered at?
less than 500mg per hour through intermitted infusion
why is a loading dose sometimes used?
to achieve therapeutic concentrations quickly
daily maintenance dose equation
Dose rate= target Cssaverage x Clearance
